The Clinical Services Core (CSC) is a central resource designed to support each step in the development, conduct, and analysis of all human subject research projects originated from or supported by the Case CFAR. Specific aims of the CSC include: Maintain and expand a comprehensive and accessible Patient Care and Research Database (PCRD). Maintain and expand a specimen repository linked to the patient care database. Provide researchers with access to patients pre-selected for interest and identified as eligible (through mining of the Patient Care and Research Database) to participate in HIV clinical trials or other research studies. Maintain, expand, and provide access to a newly established database of over 800 HIV-negative volunteers in the Cleveland area who are interested in participating in HIV research. Coordinate the exchange of clinical and laboratory data with other institutions participating in collaborative projects designed to conduct research on HIV observational data. The Case CFAR is a founding member of two such collaborations, the CFAR Network of Integrated Clinical Systems (CNICS) and the North American AIDS Cohort Collaboration on Research and Design (NAACCORD). Assist CFAR researchers in planning and designing studies that use the PCRD and the specimen repository by helping investigators formulate research questions that take full advantage of the data and specimens available through the Core. Provide biostatistical and epidemiologic support and advice to Case CFAR investigators, and provide training and faculty development in epidemiology and biostatistics.